Answer:
The value is
Explanation:
From the question we are told that
The distance of friends house from your point is 
The distance of your friends street from your street is 
The diagram illustrating this question is shown on the first uploaded image
From the diagram we can apply by Pythagoras theorem as follows

=>
=>
=>
Answer:
Ro = 8.65 [g/cm³]
Explanation:
We must remember that density is defined as the ratio of mass to volume.

where:
m = mass = 0.450 [kg] = 450 [g]
V = volumen = 52 [cm³]
Ro = density [g/cm³]
Now replacing:
![Ro = 450/52\\Ro = 8.65 [g/cm^{3} ]](https://tex.z-dn.net/?f=Ro%20%3D%20450%2F52%5C%5CRo%20%3D%208.65%20%5Bg%2Fcm%5E%7B3%7D%20%5D)
Answer:
No, it's not there.
Explanation:
For a machine to be 100% efficient, it has to be with an output which is equal to its input. But machines have an out put less than an input, hence efficiency below 100%.
Answer:
0.80865 Hz
1.23662 seconds
Explanation:
g = Acceleration due to gravity = 9.81 m/s²
l = Length of arm = 0.57 m
Length of simple pendulum is given by

The frequency is given by

The frequency is 0.80865 Hz
The time period is given by

The time period is 1.23662 seconds
Based on the law of conservation of energy, we know that we can't create energy, machines can only convert one type of energy into another. So, if we want to improve a machines's ability then we need to reduce it's loss energy (part of energy which is useless). Out of all the options only Option C fits best with it.
In short, Your Answer would be Option C
Hope this helps!